Through-Hole Vs Surface Mount: What is The Difference?

Through-Hole Vs Surface Mount: What is The Difference?

Oct 28,2020

Ever since the 1980s, there has been a debate over the superiority of through-hole PCB assembly vs surface mount PCB assembly. The through-hole PCB assembly dominated the PCB manufacturing industries until the introduction of surface mount technology. Ever since the surface mount PCB assembly method has been introduced, both these technologies are being pitted against each other. Although each of these technologies holds its share of benefits, drawbacks, and applications, the debate becomes crucial. Therefore, it is essential to know that application based comparison is essential to decide which technology is best for a specific application. This post helps in taking a constructive decisive approach towards the selection of through-hole or surface mount PCB assembly technology by shedding light on individual aspects of these types of assembly.

In order to offer a comparative perspective, let us discuss both the technologies one by one.

Through-hole PCB Assembly: What is it and how is it performed?

The through-hole mounting technology (TMT) is the pioneer method of the component mounting in the PCB assembly process. This process involves the placement of PCB components inside the drilled holes on the bare board. Earlier, the mounting was done manually and with the advancement in automation advancement, the component placement is not automated. This process demands to post mounting connections via tracing and soldering.

Let us discuss a few beneficial factors related to the through-hole PCB assembly method.

  • In TMT assembly, the connections between the components are made via the drilled holes. They are connected via trace lines and firm soldering.
  • The mechanical reliability of PCBs is higher in TMT due to the rigid interconnection between the layers. Therefore, this technology is suitable for hard-core PCB manufacturing
  • The component mounting can be performed axial or radial in the TMT. In axial component mounting, the component vertically passes via the drilled hole. In the radial type of component mounting, the component is mounted perpendicular to the drill axis, sometimes, it is mounted inside the board surface.

Despite being an old and long-term utilized technology, applications of the through-hole PCB assembly method are found mostly in military and defense PCBs, aerospace and aircraft PCBs, prototyping and testing, etc.

Surface Mount PCB Assembly: All Important Facts Analyzed

The surface mount technology (SMT) of PCB assembly was first introduced in the 1960s but was adopted in the 1980s. Ever since it was introduced, the debate over SMT vs TMT has to be triggered due to the typical benefits of these technologies. Surface mount technology (SMT) basically includes component mounting on the surface of PCB. This technology has taken a fast pace in the industry since it offers a more convenient manner of component mounting.

Let us discuss key factors of SMT that stand in contrast with TMT PCB assembly.

  • SMT involves direct component mounting on the surface, and the components are fixed by soldering.
  • Surface-mounted PCBs features “vias” that are small components, which enable interconnectivity between the layers of PBC without any hole.
  • Complex component placements can be achieved due to a reduction in complexity through drilling and tracing connections between two components.

The list of applications of SMT in PCB industries is huge. Comparatively speaking, there is a higher number of components that are being manufactured by using SMT. However, in comparative terms, TMT is considered a highly reliable technique for PCBs demanding rigidity, reliability, mechanical resistance, and durability. On other hand, SMT is suitable for PCB assemblies where the speed of assembly, manufacturing assembly are of higher importance than durability.

Considering all the above-mentioned factors of through-hole PCB assembly and surface mount PCB assembly techniques, one can make the right choice based on application requirements. However, regardless of the type of PCB assembly method one decides to adopt, it is essential to ensure the quality of the process. The PCB assembly services must be sourced from experts and trusted PCB manufacturers like Creative Hi-Tech. The company offers custom PCB design, manufacturing, and assembly services to their clients by using modern technologies.

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